The Chameleonic Nature of Platinum(II) Imidazopyridine Complexes

Pinter, Piermaria; Pittkowski, Rebecca; Soellner, Johannes; Straßner, Thomas

doi:10.1002/chem.201703908

Cited by 18 publications

(16 citation statements)

References 34 publications

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“…The solid-state emission profile of the α-polymorph (Figure 4, red curve) and emissive properties (Table 1) are well reproduced by the neat film of the emitter (Figure 4, orange curve). We suggest that the α-polymorph [11] of the second fraction showing the blue emission at different concentrations.…”

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confidence: 74%

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Polymorphic Phosphorescence from Separable Aggregates with Unique Photophysical Properties

Pinter

Hennersdorf

Weigand

et al. 2021

Chemistry A European J

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Platinum complexes aggregate into polymorphs with different intermolecular interactions leading to different photophysical properties. Strong intermolecular interactions stabilize the aggregate to such an extent that the polymorphs can be separated directly by column chromatography. Solid-state structures as well as quantum-chemical calculations confirmed the effect of the interactions on the photophysical properties.

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confidence: 74%

“…Figure 3. EEM matrix analysis[11] of the second fraction showing the blue emission at different concentrations.…”

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confidence: 99%

Polymorphic Phosphorescence from Separable Aggregates with Unique Photophysical Properties

Pinter

Hennersdorf

Weigand

et al. 2021

Chemistry A European J

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“…The use of diaryliodonium salts is well established for the arylation of a wide range of oxygen and nitrogen nucleophiles both with and without a copper catalyst. − Chen and co-workers have described a copper-free route to N -aryl pyridinium species from diaryliodonium salts and pyridinium N -oxides or sulfonamidates via a radical rearrangement; , however, the N-arylation of pyridines themselves requires a copper catalyst. , Most similar to this work describing the 1-arylation of triazoles is a recent report by Kumar et al investigating a copper-catalyzed N-arylation of [1,2,4]triazolo[4,3- a ]pyridines leading to fused triazolium salts . To our knowledge, there have been no examples described in the literature for the copper-catalyzed 1-arylation of monocyclic triazoles with diaryliodonium salts; however, the preparation of 4-aryltriazolium or 3-arylimidazolium salts via similar methods has been reported before. − …”

Section: Introductionmentioning

confidence: 79%

Catalytic Preparation of 1-Aryl-Substituted 1,2,4-Triazolium Salts

et al. 2019

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1,4-Diaryl- and 1-aryl-4-alkyl-substituted 1,2,4-triazolium salts are convenient air-stable precursors to carbenes used both as organocatalysts or as ligands for transition metal complexes. Traditionally, they are prepared via a multistep synthetic pathway with the low-yielding formation of the triazolium ring occurring in the last step. We have developed an alternative two-step synthesis involving the conversion of a primary amine or aniline derivative to the corresponding 4-substituted triazole followed by a copper-catalyzed arylation with diaryliodonium salts. This transition metal-catalyzed arylation can be carried out under mild conditions in acetonitrile and is tolerant toward both water and oxygen. Additionally, the high functional group tolerance of the protocol described here gives easy access to triazolium salts containing heterocyclic substituents or sulfides.

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“…The excited-state lifetime of the new emission band was determined as 152 ns in an air-equilibrated solution and 367 ns in a nitrogen-saturated solution. On the basis of these experimental results, we suggest that the new emission band at 550 nm of Pt1 arises from triplet excimeric emissive states . Moreover, Pt1 shows the highest quantum yield of 7.8% in nitrogen-saturated solution, indicating that the presence of the electron-withdrawing −CF 3 group reduces the nonradiative transitions and enhances the emission properties.…”

Section: Resultsmentioning

confidence: 99%

“…The emission properties of these complexes could be tuned by the intermolecular Pt···Pt and π–π stacking interactions . However, these intermolecular interactions are usually associated with a reduction in quantum yield and hinder their light-emitting-related applications . One method for realizing highly emissive platinum complexes is to introduce bulk substituents in the square-planar platinum complexes .…”

Section: Introductionmentioning

confidence: 99%

Ligand Engineering toward Deep Blue Emission in Nonplanar Terdentate Platinum(II) Complexes

Shao

Zhao

et al. 2021

Organometallics

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Eight nonplanar terdentate cyclometalated Pt(II) complexes (Pt1−Pt8) have been designed and synthesized with the general formula [Pt(N ∧ C ∧ N)Cl], where N ∧ C ∧ N represents 1,3-bis(N-methyl-N′-(pyridin-2-yl)amino)benzene (H-L) derivatives with various substituents (−CH 3 , −OCH 3 , −Cl, and −CF 3). These complexes were fully characterized via a wide array of spectroscopic and X-ray single-crystal diffraction techniques. The electrochemical, photophysical and electroluminescence properties of these compounds have been investigated. As determined by the X-ray single-crystal structures of Pt1 with −CF 3 substituents and [Pt(L)Cl] (Pt3), both of them possess a nonplanar configuration but show different intermolecular interactions. In dilute solution, all of these complexes show deep blue emission. However, the emission of the corresponding doped PMMA films can be varied from greenish yellow to deep blue by introducing electron-withdrawing (−Cl or −CF 3 ) to electron-donating (−CH 3 or −OCH 3 ) substituents. Accordingly, Pt1 with −CF 3 substituents displays concentration-dependent emission properties with an additional excimeric emission band centered at 550 nm, resulting in a greenish yellow emission in the doped PMMA film. Pt7 and Pt8 with electron-donating groups (−CH 3 for Pt7, −OCH 3 for Pt8) show deep blue emission in both solution and the doped thin films. Sky blue emission was observed in PMMA films doped with Pt2−Pt6. A bluish green organic light-emitting diode with a maximum EQE of 3.7% was fabricated using Pt7 as the dopant emitter with CIE coordinates of (0.2822, 0.3602). In addition, density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were carried out to investigate the theoretical molecular orbitals and energies of the studied complexes. This work provides an effective molecular-structure-design approach to develop deep blue phosphorescent emitters.

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The Chameleonic Nature of Platinum(II) Imidazopyridine Complexes

Cited by 18 publications

References 34 publications

Polymorphic Phosphorescence from Separable Aggregates with Unique Photophysical Properties

Polymorphic Phosphorescence from Separable Aggregates with Unique Photophysical Properties

Catalytic Preparation of 1-Aryl-Substituted 1,2,4-Triazolium Salts

Ligand Engineering toward Deep Blue Emission in Nonplanar Terdentate Platinum(II) Complexes

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